Tunneling Radiation of a Torus-Like Black Hole in Anti-de Sitter Space-Time

An extension of the Parikh-Wilczek's semi-classical quantum tunneling method, the tunneling radiation of the charged particle from a torus-like black hole is investigated. Difference from the uncharged mass-less particle, the geodesics of the charged massive particle tunneling from the black hole is not light-like, but determined by the phase velocity. The derived result shows that the tunneling rate depends on the emitted particle's energy and electric charge, and takes the same functional form as uncharged particle. It proves also that the exact emission spectrum is not strictly pure thermal, but is consistent with the underlying unitary theory. PACS Numbers: 04.70.Dy, 97.60.Lf, 05.30.Ch.     

Study of the spontaneous formation of organic layers on carbon and metal surfaces from diazonium salts

This study investigates the spontaneous grafting of different para-substituted phenyl groups on carbon and metallic surfaces from diazonium salts solutions. Glassy carbon, nickel, zinc and iron plates were allowed to react with an acetonitrile solution of aryldiazonium tetrafluoroborate salt by simple dipping. The surfaces were characterized before and after their immersion by XPS and AFM to evidence the formation of a coating on the different materials. The results are indicative of the presence of substituted phenyl groups on all the investigated surfaces. This study also aims at correlating grafting efficiency with metal reactivities and diazonium salt electronic properties by means of AFM and FT-IRRAS. For this purpose, zinc and nickel were chosen due to their opposite reducing properties and two diazonium salts were selected with electron-donor or -withdrawing para-substituents. The results tend to indicate that redox properties of both partners (diazonium + metal) are of prime importance for grafting to occur.     

含氰基的酚醛树脂及其碳纤维复合材料

含氰基的酚醛树脂，具有优异的耐高温性能和高温下的机械强度，在３１５℃下性能变化甚小；不着火，发烟量低，有良好的加工成型性能。热固化过程中氰基成三嗪环而交联，没有小分子脱出，是一类具有广泛发展前景的新型热固性树脂。     

Carbon–epoxy composites based on fibers coated with nylon 6,6: hygrothermal ageing versus interlaminar shear strength

Carbon fibers were coated in situ with a thin film of polyhexamethylene adipamide by an interfacial polycondensation technique. The modified fibers were used for the preparation of epoxy-based unidirectional composites. Specimens of these materials were immersed in water until equilibrium conditions were attained. The weight gain at equilibrium was determined as a function of the immersion temperature, the fiber volume fraction and the polyamide content deposited on the fibers. Water penetration in specimens made with uncoated carbon fibers increases when the volume fraction decreases. Introduction of the polyamide interlayer initially increases the water absorption, but reduces it at higher immersion temperatures and/or higher polyamide contents. The treated specimens were subjected to the short beam test to determine the interlaminar shear strength (ILSS). The data show that the ILSS decreases with water penetration but increases when the immersion temperature increases from 40 to 70°C. The overall performance encountered is discussed in terms of the possible roles of the polyamide interphase while taking into account mechanisms concerned with matrix plasticization, interphase degradation and residual stress relaxation.     

采用热处理方法提高MEH-PPV单层聚合物有机发光二极管发光性能的研究

对以MEH－PPV为发光层的单层聚合物有机发光二极管（OLED）器件在最佳条件下进行真空热处理，并用金相显微镜观察施加电压后器件的阴极表面形貌。发现处理后的器件阴极表面的气泡及黑斑明显减少。器件的发光性能显著提高。与未经处理的器件相比，最大相对发光强度提高了一个数量级、启亮电压降低了2．0V，半寿命提高了12．7倍。初步分析表明热处理方法提高器件发光性能的主要原因在于有效地减少了器件在工作过程中由于焦耳热产生的某些气体，从而减少阴极表面气泡及黑斑的出现，另一方面，热处理方法也增强了有机发光层与阴极接触界面的结合力，提高电子注入水平。     

Methane activation on Ni(1 1 1): Effects of poisons and step defects

We have, theoretically and experimentally, investigated the dissociation of methane on the terraces and steps of a Ni(1 1 1) surface. Using Density Functional Theory (DFT) total energy calculations combined with Ultra High Vacuum (UHV) experiments, we find that the steps exhibit a higher activity than the terraces. We have, furthermore, investigated how carbon and sulfur present on the surface will deactivate the steps, leaving only the terraces active. We find the intrinsic sticking probabilities of methane on the steps and terraces at 500 K to be 2.8 × 10⁻⁷ for the steps and 2.1 × 10⁻⁹ for the terraces, in complete agreement with our calculated difference in activation energy of 17 kJ/mol.     

Effect of carbon content on the microstructure and the cracking susceptibility of Fe-based laser-clad layer

The laser cladding of Fe-based alloys on a medium carbon steel substrate was performed using a CO₂ laser and Ar shielding gas that was blown into a molten pool. The microstructure and cracking susceptibility of the laser-clad layers were studied in terms of carbon additions. Results show that the small change of the carbon content in the alloy powders can obviously change the microstructure and properties of the layers. When the carbon content is in the range of 0.3–0.4 wt.%, the decrease of the carbon content in alloy powders will increase the hardness and toughness of the layers simultaneously under the same process parameters. As a result, crack-free coatings with high hardness can be obtained. As the carbon content increases from 0.2 wt.% to 0.4 wt.%, the segregation ratio of chromium increases, while the segregation ratios of nickel, manganese, and silicon first decrease and then increase. At the same time, a new designing principle concerning the composition and microstructure has been put forward, and the principal mechanisms of strengthening and toughening of the layers are fine-grain strengthening and low carbon martensitic phase transformation strengthening.     

Preparation of well-aligned carbon nanotubes by pyrolysis of phenolic resin in anodic alumina pores

Well-aligned carbon nanotubes (CNTs) of high quality were synthesized by pyrolysis of phenolic resin at 800 °C in anodic alumina oxide (AAO) pores under argon protection. The innocuous source materials and safe operational conditions permit this method to synthesize well-aligned CNTs in large-scale and low cost. The formation mechanism of the synthesized CNTs is also proposed in this work by a series of visual sketches and is proved with obvious evidence. Firstly, phenolic resin nanotubes form in the template pores through the evaporation of solvent. Heat treatment then transfers these tubes into CNTs.     

Preparation of nanosized ZnO using α brass

Nanosized ZnOs were synthesized on the surface of α brass coated a film of nickel catalyst at 500-700 °C under atmosphere of O₂ and CH₄ gases. The nanosized ZnOs have shapes including pillar, leaf, sheet and rod, which were determined by the synthesis temperature and the flow rates of O₂ and CH₄ gases. The nanosized ZnOs were characterized by electron microscopy including transmission electron microscope for crystal structure, morphology and high resolution images, both field emission scanning electron microscope and scanning electron microscope for morphology, and energy dispersive X-ray spectroscope equipped in electron microscope for chemical composition. A mechanism was proposed for the growth of nanosized ZnO obtained in this work.